1. Field
The subject invention is in the field of dynamo-electric machinery; i.e. machinery which converts mechanical energy into electrical energy or electrical energy into mechanical energy. More specifically it is in the field of such machinery using direct electrical current.
2. Prior Art
There is much prior art in this field. However, the basic configuration of direct current motors and generators has not changed significantly in many years and, although such equipment has been and is clearly useful and commercially successful, there has been a longstanding recognition that certain characteristics of such machinery have detracted from its functional efficiency and prevented the manufacturing costs from being even lower. One such characteristic is that the commutators in conventional motors have several poles in smaller motors and generators and many more in larger equipment. A second is that the armature windings inherently have more inductance than desired because of resulting problems with sparking at the contacts between the brushes and commutator. The inductance in the armature windings produces armature reaction which is manifested by distortion of the magnetic flux of the field, lowering efficiency, and by the aforementioned commutation problems Alleviation of these difficulties requires the use of interpoles (commutating poles) and, in many cases, compensating windings. Both the interpoles and compensating windings tend to lower overall efficiency and clearly increase manufacturing costs.
Therefore a primary objective of the subject invention is to provide direct current dynamoelectric machines in which armature inductance and the related armature reaction are virtually non-existent with the result that such machines can be more efficient than conventional direct current motors and generators. A second objective is that motors and generators made according to the subject invention be simple and economical to manufacture and thereby both more efficient and more economical to manufacture than conventional direct current motors and generators.